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Definition
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Term
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Definition
The point of an object at which all mass tends to be concentrated and where the force of gravity acts upon
Human body is 5 cm ant to S2 |
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Term
| Body Weigh Vector in normal standing (T-spine, hip, knee, ankle) |
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Definition
Ear canal -> anterior to ankle
anterior to T-spine
posterior to hip
anterior to knee
anterior to ankle |
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Term
| Three forces acting on joints |
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Definition
1. Gravity i.e. falling body weight
2. Muscle tension (active) gluts/gastroc
3. Ligamentous tension (passive) knee ext |
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Term
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Definition
Head, Arms and trunk
Composes 70% Body Weight
‘Within’ HAT - COG is ant. to T-10
HAT dominates body vector alignment
Long lever ~33cm (12in.) above the hip joints |
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Definition
| the study of FORCES applied to the body at rest or during movement |
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Definition
the study of MOVEMENTS without regard to the forces that cause the movements
ex: knee flexion ROM occurring during gait |
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Definition
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Definition
| The linear distance between the point of initial contact of one foot to the same point of initial contact on the opposite foot |
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Definition
| The linear distance between the point of initial contact (heel strike) of the ipsilateral heel |
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Definition
| The amount of time required to accomplish one stride (= 2 step) |
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Definition
The number of steps per minute
Normal = 90-120 steps/minute |
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Term
| Spatial descriptors of gait |
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Definition
Stride length
Step length
Step width (base of support)
Toe out |
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| Temporal descriptors of gait |
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Definition
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Definition
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Definition
Weight acceptance
Single limb support
Limb advancement |
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Definition
Initial contact
Loading response
Mid-stance
Terminal stance
Pre-swing
Initial swing
Mid-swing
Terminal swing |
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Term
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Definition
Begins: initial contact
Ends: Toe off (foot the ground |
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Term
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Definition
Def: period when foot is in the air
Begins: toe removed from the floor
Ends: right before initial contact |
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Term
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Definition
initial and terminal
20% of the gait cycle (more stable)
Initial double stance - Marks beginning of gait cycle
The time both feet are in contact with ground following initial contact
Begins with floor contact by opposite foot |
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Definition
40% of the gait cycle per leg (less stable)
Begins when opposite foot is lifted |
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Term
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Definition
Stance = 60%
Initial double stance =10%
Single limb stance =40%
Terminal double stance =10%
Swing = 40% |
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Term
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Definition
Considered most demanding of 3 tasks
3 functional goals of this task;
1. Shock absorption
2. Initial stabilization of limb
3. Preservation of momentum |
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Term
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Definition
Task of one limb to maintain body weight
Stability and progression |
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Definition
Goals of this task include;
lifting limb at toe off
advancing limb
preparation for next stance period |
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Term
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Definition
Objective:
Positioning limb for stance
Exact moment when
foot just touches floor (IC)
- oppsite limb: end of Terminal Stance |
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Term
| Phase 2: Loading Response |
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Definition
Objectives:
Shock absorption
Weight transfer to forward limb
Preservation of progression
Begins with Initial Contact and continues until the other foot is lifted for swing
Opposite limb - Pre-Swing |
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Term
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Definition
Objectives:
Progression over stationary foot
Limb/trunk stability
Begins just after the opposite foot is lifted and continues until body weight is aligned over the stance forefoot
Opposite: MSw |
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Term
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Definition
Objective:
Progression of body beyond supporting foot
Begins with heel rise of the stance limb and continues until the opposite foot strikes the ground (IC)
Opp Limb - Term Swing - Init Contact
Gastroc working to control tibia |
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Term
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Definition
Objective;
Position of limb for swing
Begins with Initial Contact of the opposite limb and ends with ipsilateral toe-off
Final phase of stance (5)
Weight is shifted to opposite leg (loading response) in preparation for swing of unloaded limb
Opposite lim: LR
foot is it in contact with the ground |
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Term
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Definition
Objectives:
Clear foot of floor
Advance limb from trailing position
Begins with lift of the foot (toe-off) from the floor and ends when the swinging foot is opposite the stance foot
Opposte limb: early Mid stance |
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Term
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Definition
Objectives:
Limb advancement
Foot clearance from floor
Begins as the swinging limb is opposite the stance limb and ends when the swinging limb is forward and the tibia is vertical
Opp Limb: Later Mid Stance |
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Term
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Definition
Objectives:
Complete limb advancement
Prepare limb for stance
Begins with a vertical tibia and ends when the foot strikes the floor (Initial Contact)
Opposite limb: Terminal stance |
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Term
| When is the Center of Gravity highest during gait |
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Definition
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Term
| When is center of gravity lowest |
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Definition
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Term
| Minimizing excursion of COP is achieved by these 2 motions |
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Definition
Pelvic motion
Knee & ankle motion |
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Term
| Contralateral hip drop occurs during |
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Definition
| during loading of opposite limb (swing limb) |
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Term
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Definition
| during and just after loading of ipsilateral limb (stance limb) |
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Term
| horizontal hip rotation occurs |
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Definition
| as the swing (opposite) limb advances (swing side) |
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Term
| Minimizing COG excursion knee and ankle combinations |
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Definition
Pf w/ knee flexion
Df w/ knee extension |
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Term
| Knee and ankle motion during initial double support |
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Definition
| After IC/during LR: pf & one flx -> foot flat & shock absorb |
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Term
| Knee and ankle motion Midstance |
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Definition
| Knee ext with df (closed chain) -> stability in stance body comes over foot |
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Term
| Terminal double limb support: knee and ankle motion |
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Definition
| Knee flex & pf for pre-swing (preparing for clearance) |
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Term
| Mechanism of Energy Conservation |
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Definition
by using passive momentum vs. active muscle action; i.e. use muscle only when necc
Ex: knee flx during initial swing: passive
Ex: muscles activate only when body alignment creates antagonistic torque
i.e. BWV posterior to knee or anterior to hip |
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Term
| What are rockers, and what do they do? |
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Definition
Allow momentum to continue by providing propulsive impetus.
1) Decrease energy cost
2) Preserve momentum |
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Term
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Definition
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Term
| Sagittal Plane: Initial contact |
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Definition
Ankle - is neutral, anterior tibialis positions foot, isometric contraction
Knee is in 0 degrees - 5 deg of - Quads and hams stabilize knee
Hip is in 20 deg of flexion - Hip extensors (glut max & hams) are active (isometric) preventing collapse into flexion |
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Term
| Sagittal Plane: Loading Response |
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Definition
Ankle - 5-10 degrees of rapid plantaflexion, eccentric contraction of Tib Anterior, Initiates forward translation of tibia - flexing knee (pf/kf combo!!) Heel rocker
Knee flexes to 20deg - Quads absorb ___ and prevents collapse of the knee - eccentric contraction
Hip is in flexion, Hip extensors (glut max & hams) fire concentrically to counteract high intensity flexion torque in order to stabilize & assist into extension. Most demand on glutes right here! |
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Term
| Sagittal Plane: Mid-stance |
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Definition
Ankle - PF to 5 degrees DF, ankle rocker , Eccentric Grastroc firing controls forward translation of tibia
knee - GRFV is anterior to the knee causing knee to extend without muscle activation
Hip - GRV is posterior to causing hip extension without muscle activation |
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Term
| Sagittal Plane: Terminal Stance |
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Definition
Ankle - GRFV progress toward MT heads, allowing the heel to rise. Eccentric GS prevents tibial collapse. DF inc to 10 degrees. GS switches from ECC to iso, Forefoot rockers, 80% of acceleration force
Knee - stays stable near extension due to G/S complex
Hip -extends to 20 deg, remains stable by passive action of anterior hip capsule. momentum causes hyperextension |
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Term
| Sagittal plane: Pre-Swing |
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Definition
Stance limb is unloaded, allowing ankle to PF over fixed fulcrum.
Ankle - PF to 15-20 degreees, GS activity
Knee - unlocked by motion at ankle, rapid knee flexion to 40 deg. Passive motion.
Hip - falls forward when knee unlocks, causes remains in neutral. BWV moves anterior to to hip |
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Term
| Sagittal Plane: Initial Swing |
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Definition
Ankle - PF decrease to 5 deg from 20, concentric DF
Knee - flexes to 60 deg. passive in normal pace, (slower pace: gastroc, sartorius, and gracilis) assist concentrically
Hips begins to flex, 15 deg, iliopsoas concentric action |
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Term
| Sagittal Plane: Mid-swing |
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Definition
ankle - Ankle DF to 0 degrees achieving foot clearance
Knee - begins to extend, goes from 60 to 25 deg, caused by momentum, no muscle action required
Hip - 25 degrees of hip flexion achieved, hip flexor action ceases |
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Term
| Sagittal plane: Terminal swing |
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Definition
Ankle - remain in 0, AT is active, pre-position of foot for initial contact or heel rocker
Knee - Knee extends to neutral, Hamstrings decelerate thigh & leg movement into extension (decelerate) thigh into extension (decelerate), Quads prepare extended knee for initial contact.
Hip is still and 25deg from Msw, Hams are ECC decelerating thigh & Gut Max initiates activity to stabilize hip in preparation of wt acceptance |
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Term
| So, what is the full sagittal plane ROM at each joint |
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Definition
Hip 20 ext to 25 flx
Knee 0 ext to 60 flx
0-60 stance; up to 60 in swing
Ankle 10*** df to __ pf |
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Term
| The Pelvis is considered to have three rotations: |
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Definition
1.) Ant./Post. pelvic tilt…sagittal
2.) Pelvic drop ….coronal plane
3.) Pelvic Rotation ….transverse |
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Term
| Ant/Post. Pelvic motion during |
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Definition
Magnitude = 8 degrees (4 each)
Max Ant. pelvic tilt at initial contact
Max Post. pelvic tilt at PSw-toe off
Reverses tilt in midstance and midswing |
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Term
| Pelvic shift occurs during: |
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Definition
LR, shift up 1-2 in laterally over the stance limb in prep for single support phase, for preservation of momentum
During LR, eccentric action of gluteus medius lowers pelvis
During Mid-Stance -> Terminal Stance Concentric action of gluteus medius levels the pelvis |
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Term
| Purpose of pelvic rotation |
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Definition
Pelvis rotates forward (IR) on the swing side & backwards (ER) on the stance side
Rotation prevents COG from falling as far – reduces impact
Pelvic rotation serves to elongate stride |
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Term
| Pelvic rotation during gait |
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Definition
Maximal IR occurs during IC, leg forward
Maximal ER occurs during pre-swing/toe off
Magnitude of ROM = 8-10 degrees
Pelvic rotation is neutral at midstance and midswing when the limbs are directly opposite each other |
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Term
| Hip transverse gait motion |
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Definition
At the Hip: If the foot is to stay neutral to the plane of progression, the hip must rotate in the opposite direction of the pelvis
For example: the hip must gradually externally rotate in swing as the pelvis internally rotates or else toes point in |
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Term
| Tranverse: trunk rotation |
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Definition
Trunk rotates ~ 5 degrees
Causes shoulder rotation and arm swing |
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Term
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Definition
Initial Contact - neutral
LS-> MST - Calcaneus everts 5 deg, mid-tarsal jt unlock - foot pronation, allows for shock absorption. Post Tib fires ECC, tibia Internally rotates
Tst - Gradual calcaneal inversion, Mid-tarsal joint loscts foot (supination), provides stability for propulsion. Tibia externally rotates. Post tib fires concentrically
Swing - stays in neutral |
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Term
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Definition
IC: 25 degrees df
End of LR: neutral
Terminal stance (heel-off): ~20 degree df
PrSw and push-off: 55*** degrees df |
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